ADAPTIVE WEIGHT FUNCTION BASED ON ENHANCED LEAST RESISTANCE FOR ROUTING ALGORITHMS IN OPTICAL WDM NETWORKS

摘要

The main objective of this research paper is to enhance the efficiency of routing and wavelength assignment (RWA) for optical Wavelength Division Multiplexing (WDM) networks. Normally, the transport protocol in WDM networks is based on connection-oriented transmission that in physical it uses circuit-switching technique. Therefore, when a session request is given, the hard task of routing and wavelength assignment is how to determine the satisfied path between two nodes, and also to assign an available set of wavelengths along this path. To overcome these problems, we have proposed a new approach, called Enhanced Least Resistance (ELR) algorithm, in order to achieve the effective routing and wavelength assignment that can find the least resistant light-path for user's requirement. The link weight function is considered as the main important factor for route selection in ELR algorithm. And this function is calculated by using a determination factor of the number of wavelengths that are being used currently and are supposed to be available after a certain time. In according to ELR algorithm, the session requests from users will be routed on the links that has the least number of link weights by using Dijkstra's shortest path algorithm. This means that the selected light-path will have the least resistance, i.e., low blocking probability. The performance ELR is investigated by using Abilene network as a simulation model. The simulation results show that the proposed ELR algorithm can achieve better performance in terms of the blocking probability when comparing with the well-known traditional mechanism.